Venetian blind assemblies have been utilized in window units where the blind assembly is positioned behind glazing in any number of different ways. For example, the blind assembly may be adjacent a single pane of glass, may be positioned between two panes, or even positioned in a triple pane window unit. In those units having two or more panes, blind assemblies may in addition be sealed with respect to the panes such that the unit forms a hermetically sealed window unit to provide superior insulation properties. In all forms of units, including single and multiple pane constructions and unsealed and hermetically sealed constructions, it is desirable to have a single effective pivoting or tilting control mechanism by which the tilt of individual slats of the blind assembly may be easily and accurately regulated using a minimum of force and where the degree of force necessary to pivot or tilt the slats remains substantially uniform during the complete range of tilting.
It is also desirable in order to facilitate placement in a window unit that the venetian blind be fully reversible in a window opening, that is to say, that the top and bottom ends of the blind be reversible in the unit or that the top and bottom ends of the unit be reversible. This reversible feature in turn requires a tilting transfer mechanism which may work equally as well in one position of the blind assembly or window unit as in a reverse position.
Further it is desirable in window units having two or more spaced panes that the slats of the blind assembly in the open position occupy as much of the space between the panes as possible in order to reduce expense of blind assembly and to reduce operating forces. If smaller width slats are utilized where the width of the slat is substantially less than the space between panes, more slats will be required to completely close the window opening thus increasing expense of manufacture and assembly as well as forces necessary to operate the tilting mechanism.
Magnetic couplings have been proposed for hermetically sealed window units to connect an operable member exterior of the unit to a blind operating element on the interior of the unit. See for example U.S. Pat. No. 3,022,549 dated Feb. 27, 1962 and U.S. Pat. No. 3,129,471 dated Apr. 21, 1964. A problem with such magnetic couplings to date has been to design one which is small in size and which will at the same time have sufficient coupling strength to enable the slats of the blind to be tilted throughout their complete operating range. A further problem with some of the magnetic couplings to date, and particularly when used in units having only a small spacing between glazings, is that when the operating element is connected by a connecting means, for example a tape cable, to a hanger pivot member supporting the slats, lateral forces will be imparted on the connecting means to displace it inwardly towards the slats due to the thickness of the operating element. This inward displacement may result in the connecting means interferring or binding with the edge of slats adjacent the operating element resulting in deformation of these slats and increase in operating force necessary to tilt the slats.
It has been proposed to have cutouts in the slats adjacent the operating element to accommodate the thickness of the operating element to reduce the inward displacement of the connecting means. However, when the connecting means comprises a slat supporting cable, separate provision has to be made to prevent longitudinal displacement of the slats since the tape cables in the area of the cutouts no longer will prevent such longitudinal displacement.
Venetian blind assemblies are in addition conventionally suspended in a window or other frame opening from a complex headrail assembly which contains tilting and lifting hardware. Where greater stability for the blind assembly is required and/or where the blind assembly is not required to be raised or lowered, it may alternatively be suspended within the opening between special heavy top and bottom rails or slats. Such rails are pivotally mounted in the frame opening and the suspension for slats intermediate the rails is secured to the rails. These headrail assemblies and special top and bottom rails are much more expensive than the balance of the blind assembly. Further, since the headrail assemblies and top and bottom rails or slats comprise different components than the rest of the blind assembly, they necessarily complicate and increase the cost of inventory. The use of special top and bottom rails or slats results in a nonuniform coverage of the frame openings and gaps appearing at the suspension edges of the blind assembly.
Since color matching is a very important consideration from an aesthetic viewpoint, it is necessary that the components comprising the headrail assemblies and special top and bottom rails be color matched with the intermediate slats making up the major portion of the blind assembly. This further adds to the cost and complexity of inventory and of the complete blind assembly.
It is therefore an object of my invention to provide for a magnetic coupling connecting an exterior operable control element with an interior operating element of a tilting actuating mechanism of a venetian blind assembly positioned in a window unit where the coupling is small in size and does not interfere with the movement of the slats.
It is a further object of my invention to provide for a magnetic coupling which will cooperate with cutouts in slats to reduce inward displacement of a connecting means extending between the operating element and a hanger pivot member supporting the slats and which at the same time will eliminate the need for any additional means to prevent longitudinal displacement of the slats having cutouts with respect to the connecting means.
It is a still further object of the invention to provide for a hanger pivot member for supporting a plurality of slats which eliminates need of special slats and which at the same time will assure that the force necessary to tilt the slats will remain the same throughout tilting movement of the slats.